1. Field of the Invention
The present invention relates generally to article supports, hooks, loops, and etc., and more particularly to a closed loop which is formed of a length of preferably flame resistant and electrically non-conductive flexible material. The loop is used to support and suspend articles such as electrical cables, pneumatic and hydraulic lines, ventilation ducts, etc. in the mining industry, and has further applications in many other industries such as suspending parts being painted from an overhead conveyor system, as well as other applications where good strength and resistance to flame and industrial chemicals is required.
2. Description of the Related Art
Many industries require some means of temporarily supporting or suspending various articles for various purposes, and often have need of a simple yet durable strap or loop which may be used as a hanger for various parts and components. Accordingly, various such devices have been developed in the past, but all have had one or more deficiencies which have rendered them unsuitable for use in demanding industries such as underground mining, where flame resistance, electrical non-conductivity, resistance to chemicals, and good strength, durability, and reliability are absolutely required.
In the past, the various devices manufactured for such purposes have not included all of the above properties, and moreover were not necessarily formed of highly visible materials providing for ease of visibility in darkened areas such as mines land the like. Moreover, such hanger loops, when formed of twisted or braided rope material, were often closed using means which were prone to slippage or damage, thus allowing the loop to open and release any articles being supported thereby. The present hanger responds to each of the above problems and deficiencies by using a suitable material, and forming a closed loop using that material, which is completely resistant to opening when strain is placed upon the loop. A discussion of the related art of which the inventors are aware, and its differences and distinctions from the present invention, is provided below.
U.S. Pat. No. 3,686,848 issued on Aug. 29, 1972 to Robert Miller et al. describes a Highly Resilient Polypropylene Yarn which is particularly suited for carpeting and upholstery. No mention is made of the flame resistance or other industrially desirable properties of the material, and no disclosure is made of any specific rope or loop construction using the Miller et al. yarn.
U.S. Pat. No. 3,690,057 issued on Sep. 12, 1972 to Alan H. Norris describes Anti-Static Yarn And Fabrics wherein at least some of the yarn filaments are coated with a film including an electrically conductive metal. This teaches away from the material of the present invention, which is preferably electrically non-conductive.
U.S. Pat. No. 3,738,958 issued on Jun. 12, 1973 to Henry N. Paul 3rd describes a Synergistic Flame Retarding Composition For Polypropylene Of 1, 2, 3, 4, 5-Pentabromo-6-Chlorocyclohexane, Tetrabromophthalic Anhydride And Antimony Trioxide. While the present invention may utilize polypropylene rope material treated with the above or similar flame retardant chemicals, the Paul 3rd disclosure is silent regarding the application of the chemicals to fiber materials other than carpeting or the like. No disclosure is made of the formation of closed hanger loops using polypropylene rope material, as provided by the present invention.
U.S. Pat. No. 3,949,451 issued on Apr. 13, 2976 to Hugh Bunn describes a Safety Hook Snap Assembly comprising a spring loaded closure which serves to close two areas of the device simultaneously. While the present hanger may utilize such a device, as well as other snap hock, D-ring, etc. devices, Bunn does not disclose any form of closed rope loop to which his device may attach.
U.S. Pat. No. 4,257,221 issued on Mar. 24, 1981 to Arthur L. Feinberg describes a Fire Resistant Fiber Blend wherein a fire resistant yarn is woven with a polyester or other yarn material. While the resultant material may be suitable for use in clothing, it is not suitable for the production of rope and other elongate materials requiring high tensile strength, as in the present rope hangers. Moreover, Feinberg is silent regarding the formation of his yarns into rope, or a rope hanger according to the present invention.
U.S. Pat. No. 4,534,262 issued on Aug. 13, 1985 to Richard C. Swenson describes a Safety Mooring Line comprising an outer wrap of Nylon (tm) and two concentric inner lines of Kevlar (tm). The inner Kevlar core is formed to provide supplementary strength if the outer Nylon load bearing component breaks. No particular formation of a rope hanger loop is disclosed by Swenson.
U.S. Pat. No. 4,930,194 issued on Jun. 5, 1990 to Jean P. Frechin describes a Snap Hook For Use In Climbing, Pot Holing Or Similar Activities. The device comprises a D-ring with a specially formed connecting end between the hinged link and its adjacent ring member when the ring is closed. While the present rope loop may make use of the Frechin device, Frechin does not disclose any rope or other line or loop to which his device may be secured.
U.S. Pat. No. 5,116,681 issued on May 26, 1992 to Perry H. Lin describes Anti-Static Yarns Containing Polystyrene. The material includes a polypropylene or other material which is blended with electrically conductive carbon. This teaches away from the present, preferably electrically non-conductive material from which the present rope hanger loop is formed.
U.S. Pat. No. 5,130,069 issued on Jul. 14, 1992 to Raymond F. Tietz et al. describes a Process For Producing Dyeable Hot-Bulked Polypropylene Fibers Modified Wlth A Copolyamide. While the present invention preferably utilizes a polypropylene material and may include strands of specific color(s), Tietz et al. are silent regarding the use of their fibers in forming a closed loop hanger, as provided by the present invention.
U.S. Pat. No. 5,329,728 issued on Jul. 19, 1994 to Glenn A. Ray describes a Plant Pot Hanger comprising an open metal clip adapted to secure to the edge of a hanging plant pot or drain saucer for such a pot. The device is not suited for use with the present invention, nor is any closed rope loop disclosed in the Ray patent.
U.S. Pat. No. 5,521,003 issued on May 28, 1996 to Ying-Cheng Lo et al. describes a Flame Retardant Composition comprising a blend of polypropylene with ethylene and propylene. No fibers produced from the material are disclosed, nor is any form of rope, or any means of forming a closed loop from such rope, disclosed.
U.S. Pat. No. D-303,212 issued on Sep. 5, 1989 to William G. Crowle illustrates a design for an Interlocking Snap-Hook Unit, comprising two interlinked flat components. No closed rope hanger loop is disclosed, and no means is disclosed to secure the unit to another article.
U.S. Pat. No. D-303,493 issued on Sep. 19, 1989 to William J. B. Jacobs illustrates a design for a Hanger Unit For Cable Or Similar Articles, comprising a closed rope loop having an S-hook depending therefrom. While the external appearance of the design is similar to the appearance of the present hanger invention, the Jacobs design patent does not disclose any means of forming such a loop, nor is any disclosure made of the materials, flame retardation, electrical conductivity, or coloring of the device, each of which properties are provided for in the present invention.
In addition to the above patent publications, the inventors are aware of several products which have been manufactured for the mining industry, and particularly for the coal mining industry in West Virginia, to perform essentially the same function as the present invention. Elk Sales & Service Co., Southern Safety Sign & Manufacturing Co., and Shawnee Hills of Danville, W.Va., each produce a braided polypropylene loop in which the two ends are each spliced into the opposite hollow core to form a closed loop. No knotting of any of the strands of the rope about other strands, is apparent, while such knotting is used in combination with an interweaving of the two rope ends in the present rope loop hanger invention.
Adams Distributors, McJunkin Corporation, and Mine Cable Service Co. each manufacture a rope loop of twisted (not braided) material, with the two ends being crimped together using a hog ring, split washer, or similar metal attachment. And finally, Bailey Brothers produces a braided rope loop in which an S-hook is an integral part of the closure, with the two ends of the loop each being passed around the body of the hook and inserted back into the hollow core of the braided material. The two ends thus formed are only connected by the S-hook, and do not connect directly together, as in the knotted and interwoven ends of the present rope hanger loop of the present invention.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.